This and a companion paper present a practical calculation technique for optimization of HVAC duct systems. This technique is based on the new numerical method called the T-Method. Lifecycle cost was selected as the objective function, and there are constraints such as pressure balancing, nominal duct sizes, preselected ducts, air velocity, and installation limitations.

Tables were developed to determine electrical energy costs, escalation rates, and duct costs. The T-Method consists of three steps performed in series: System condensing, Fan selection, and System expansion. The theory of the method is presented in Part I. The step-by-step calculation procedure and examples are presented in Part II, a companion paper. A comprehensive explanation of each step, including specially designed input forms and formulas, is in Part II with many examples which confirm the practicality of the T-method. Economic analysis of the example in the ASHRAE - 1985 Handbook showed that significant cost savings are obtainable.

Units: Dual